HOUSTON — A proposal to turn the iconic but shuttered Houston Astrodome into a massive indoor park and build a tree-lined green space around the structure could cost nearly $243 million, according to a report released Monday by a nonprofit research group focused on land use.

The report by the Urban Land Institute is part of an effort by officials in Houston's Harris County as well as preservation groups and local residents to save the Astrodome from potential demolition.

A panel from the Washington, D.C.-based land institute had visited Houston and previously released some of the details of its plan in December.

"The panel concluded that the Astrodome can and should live on," the land institute said in its final report.

The group's report calls for creating a massive indoor park within the stadium, with spaces for exercise and biking trails and indoor rock climbing, as well as new underground parking. The outside areas around the stadium would be converted into tree-lined green spaces.

The land institute also said its plan would provide space that could be used by the Houston Texans and the Houston Livestock Show and Rodeo, both of which use NRG Stadium next door.

Harris County Judge Ed Emmett — who first proposed the idea for the indoor park last year — said county commissioners will review the report at its March 31 meeting.

"What is heartening about this is (the land institute) recognized the iconic nature of the building. They identified it as having the potential to be a grand space for the community," Emmett said.

Emmett and other county officials in May plan to visit an airship hangar in Brandenburg, Germany, that has been converted into a giant indoor tropical theme park. Emmett said county officials hope to get some tips from their German counterparts.

The future of the structure has been in limbo since voters in 2013 didn't authorize $217 million in bonds to turn it into a multipurpose special events center. While the Astrodome is not in any immediate danger of being demolished, local officials have struggled to find an alternative use. Over the years, some proposals — including a water park and a sports memorabilia museum — have not gained much traction, while others proposals have sought to demolish the stadium, which had become an eyesore in recent years but is now being cleaned up.

The land institute said its proposal would need to be paid through a private-public partnership.

Tom Eitler, vice president of advisory services for the land institute, said the $243 million price tag is just an estimate but "it gives a feel for the kind of money they will need to do these changes."

Opened in 1965, the so-called Eighth Wonder of the World once housed MLB's Astros and the NFL's former Oilers, but hasn't been home to a sports team since 1999 and has been closed to all events since 2009.

The world's first multipurpose domed stadium is also under consideration for a "state antiquities landmark" designation from the Texas Historical Commission that would make it more difficult to tear it down.

The stadium's most prominent use in recent years was as a shelter for Louisiana residents displaced by Hurricane Katrina in 2005. The National Park Service has added the Astrodome to its National Register of Historic Places.